Acoustic Impedance Tests: Objective tests of middle ear function based on the difficulty (impedance) or ease (admittance) of sound flow through the middle ear. These include static impedance and dynamic impedance (i.e., tympanometry and impedance tests in conjunction with intra-aural muscle reflex elicitation). This term is used also for various components of impedance and admittance (e.g., compliance, conductance, reactance, resistance, susceptance).Acoustics: The branch of physics that deals with sound and sound waves. In medicine it is often applied in procedures in speech and hearing studies. With regard to the environment, it refers to the characteristics of a room, auditorium, theatre, building, etc. that determines the audibility or fidelity of sounds in it. (From Random House Unabridged Dictionary, 2d ed)Transducers: Any device or element which converts an input signal into an output signal of a different form. Examples include the microphone, phonographic pickup, loudspeaker, barometer, photoelectric cell, automobile horn, doorbell, and underwater sound transducer. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)Electric Impedance: The resistance to the flow of either alternating or direct electrical current.Ultrasonography: The visualization of deep structures of the body by recording the reflections or echoes of ultrasonic pulses directed into the tissues. Use of ultrasound for imaging or diagnostic purposes employs frequencies ranging from 1.6 to 10 megahertz.Plethysmography, Impedance: Recording changes in electrical impedance between electrodes placed on opposite sides of a part of the body, as a measure of volume changes in the path of the current. (Stedman, 25th ed)Cardiography, Impedance: A type of impedance plethysmography in which bioelectrical impedance is measured between electrodes positioned around the neck and around the lower thorax. It is used principally to calculate stroke volume and cardiac volume, but it is also related to myocardial contractility, thoracic fluid content, and circulation to the extremities.Dielectric Spectroscopy: A technique of measuring the dielectric properties of materials, which vary over a range of frequencies depending on the physical properties of the material. The technique involves measuring, over a range of frequencies, ELECTRICAL IMPEDANCE and phase shift of an electric field as it passes through the material.Hearing Disorders: Conditions that impair the transmission of auditory impulses and information from the level of the ear to the temporal cortices, including the sensorineural pathways.Defecography: Radiographic examination of the process of defecation after the instillation of a CONTRAST MEDIA into the rectum.Veterans: Former members of the armed services.Reflex, Acoustic: Intra-aural contraction of tensor tympani and stapedius in response to sound.Hearing Loss: A general term for the complete or partial loss of the ability to hear from one or both ears.Audiometry: The testing of the acuity of the sense of hearing to determine the thresholds of the lowest intensity levels at which an individual can hear a set of tones. The frequencies between 125 and 8000 Hz are used to test air conduction thresholds and the frequencies between 250 and 4000 Hz are used to test bone conduction thresholds.Cochlea: The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH.Tensor Tympani: A short muscle that arises from the pharyngotympanic tube (EUSTACHIAN TUBE) and inserts into the handle of the MALLEUS. This muscle pulls the handle medially thus controlling the tension and movement of TYMPANIC MEMBRANE.Stapedius: A tiny muscle that arises from the posterior wall of the TYMPANIC CAVITY of MIDDLE EAR with its tendon inserted onto the neck of the STAPES. Stapedius pulls the stapes posteriorly and controls its movement.Hyperacusis: An abnormally disproportionate increase in the sensation of loudness in response to auditory stimuli of normal volume. COCHLEAR DISEASES; VESTIBULOCOCHLEAR NERVE DISEASES; FACIAL NERVE DISEASES; STAPES SURGERY; and other disorders may be associated with this condition.Ear Ossicles: A mobile chain of three small bones (INCUS; MALLEUS; STAPES) in the TYMPANIC CAVITY between the TYMPANIC MEMBRANE and the oval window on the wall of INNER EAR. Sound waves are converted to vibration by the tympanic membrane then transmitted via these ear ossicles to the inner ear.Chorda Tympani Nerve: A branch of the facial (7th cranial) nerve which passes through the middle ear and continues through the petrotympanic fissure. The chorda tympani nerve carries taste sensation from the anterior two-thirds of the tongue and conveys parasympathetic efferents to the salivary glands.Tympanic Membrane: An oval semitransparent membrane separating the external EAR CANAL from the tympanic cavity (EAR, MIDDLE). It contains three layers: the skin of the external ear canal; the core of radially and circularly arranged collagen fibers; and the MUCOSA of the middle ear.Scala Tympani: The lower chamber of the COCHLEA, extending from the round window to the helicotrema (the opening at the apex that connects the PERILYMPH-filled spaces of scala tympani and SCALA VESTIBULI).Syndrome: A characteristic symptom complex.Down Syndrome: A chromosome disorder associated either with an extra chromosome 21 or an effective trisomy for chromosome 21. Clinical manifestations include hypotonia, short stature, brachycephaly, upslanting palpebral fissures, epicanthus, Brushfield spots on the iris, protruding tongue, small ears, short, broad hands, fifth finger clinodactyly, Simian crease, and moderate to severe INTELLECTUAL DISABILITY. Cardiac and gastrointestinal malformations, a marked increase in the incidence of LEUKEMIA, and the early onset of ALZHEIMER DISEASE are also associated with this condition. Pathologic features include the development of NEUROFIBRILLARY TANGLES in neurons and the deposition of AMYLOID BETA-PROTEIN, similar to the pathology of ALZHEIMER DISEASE. (Menkes, Textbook of Child Neurology, 5th ed, p213)Metabolic Syndrome X: A cluster of metabolic risk factors for CARDIOVASCULAR DISEASES and TYPE 2 DIABETES MELLITUS. The major components of metabolic syndrome X include excess ABDOMINAL FAT; atherogenic DYSLIPIDEMIA; HYPERTENSION; HYPERGLYCEMIA; INSULIN RESISTANCE; a proinflammatory state; and a prothrombotic (THROMBOSIS) state. (from AHA/NHLBI/ADA Conference Proceedings, Circulation 2004; 109:551-556)Nephrotic Syndrome: A condition characterized by severe PROTEINURIA, greater than 3.5 g/day in an average adult. The substantial loss of protein in the urine results in complications such as HYPOPROTEINEMIA; generalized EDEMA; HYPERTENSION; and HYPERLIPIDEMIAS. Diseases associated with nephrotic syndrome generally cause chronic kidney dysfunction.Sjogren's Syndrome: Chronic inflammatory and autoimmune disease in which the salivary and lacrimal glands undergo progressive destruction by lymphocytes and plasma cells resulting in decreased production of saliva and tears. The primary form, often called sicca syndrome, involves both KERATOCONJUNCTIVITIS SICCA and XEROSTOMIA. The secondary form includes, in addition, the presence of a connective tissue disease, usually rheumatoid arthritis.Abnormalities, MultipleTurner Syndrome: A syndrome of defective gonadal development in phenotypic females associated with the karyotype 45,X (or 45,XO). Patients generally are of short stature with undifferentiated GONADS (streak gonads), SEXUAL INFANTILISM, HYPOGONADISM, webbing of the neck, cubitus valgus, elevated GONADOTROPINS, decreased ESTRADIOL level in blood, and CONGENITAL HEART DEFECTS. NOONAN SYNDROME (also called Pseudo-Turner Syndrome and Male Turner Syndrome) resembles this disorder; however, it occurs in males and females with a normal karyotype and is inherited as an autosomal dominant.Cochlear Aqueduct: A fine channel that passes through the TEMPORAL BONE near the SCALA TYMPANI (the basilar turn of the cochlea). The cochlear aqueduct connects the PERILYMPH-filled bony labyrinth to the SUBARACHNOID SPACE.Structure Collapse: Failure in built environment with loss of functional integrity.Cerebrospinal Fluid Pressure: Manometric pressure of the CEREBROSPINAL FLUID as measured by lumbar, cerebroventricular, or cisternal puncture. Within the cranial cavity it is called INTRACRANIAL PRESSURE.Pressure: A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Extracellular Fluid: The fluid of the body that is outside of CELLS. It is the external environment for the cells.Accidents, HomeMaple Syrup Urine Disease: An autosomal recessive inherited disorder with multiple forms of phenotypic expression, caused by a defect in the oxidative decarboxylation of branched-chain amino acids (AMINO ACIDS, BRANCHED-CHAIN). These metabolites accumulate in body fluids and render a "maple syrup" odor. The disease is divided into classic, intermediate, intermittent, and thiamine responsive subtypes. The classic form presents in the first week of life with ketoacidosis, hypoglycemia, emesis, neonatal seizures, and hypertonia. The intermediate and intermittent forms present in childhood or later with acute episodes of ataxia and vomiting. (From Adams et al., Principles of Neurology, 6th ed, p936)Wood: A product of hard secondary xylem composed of CELLULOSE, hemicellulose, and LIGNANS, that is under the bark of trees and shrubs. It is used in construction and as a source of CHARCOAL and many other products.Acer: A plant genus of the family ACERACEAE, best known for trees with palmately lobed leaves.Receptors, Cell Surface: Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.Palate: The structure that forms the roof of the mouth. It consists of the anterior hard palate (PALATE, HARD) and the posterior soft palate (PALATE, SOFT).Tape Recording: Recording of information on magnetic or punched paper tape.Audiology: The study of hearing and hearing impairment.Speech-Language Pathology: The study of speech or language disorders and their diagnosis and correction.Hearing Tests: Part of an ear examination that measures the ability of sound to reach the brain.Dissertations, Academic as Topic: Dissertations embodying results of original research and especially substantiating a specific view, e.g., substantial papers written by candidates for an academic degree under the individual direction of a professor or papers written by undergraduates desirous of achieving honors or distinction.Economic Development: Mobilization of human, financial, capital, physical and or natural resources to generate goods and services.Search Engine: Software used to locate data or information stored in machine-readable form locally or at a distance such as an INTERNET site.Information Storage and Retrieval: Organized activities related to the storage, location, search, and retrieval of information.PubMed: A bibliographic database that includes MEDLINE as its primary subset. It is produced by the National Center for Biotechnology Information (NCBI), part of the NATIONAL LIBRARY OF MEDICINE. PubMed, which is searchable through NLM's Web site, also includes access to additional citations to selected life sciences journals not in MEDLINE, and links to other resources such as the full-text of articles at participating publishers' Web sites, NCBI's molecular biology databases, and PubMed Central.Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.User-Computer Interface: The portion of an interactive computer program that issues messages to and receives commands from a user.Software: Sequential operating programs and data which instruct the functioning of a digital computer.

Confirmation of deafness in infancy. (1/154)

AIM: To assess delay in confirming hearing impairment in infants identified by universal neonatal screening and to investigate the causes. PATIENTS: Infants identified from 25 199 babies screened from January 1992 to December 1997. METHODS: A two stage transient evoked oto-acoustic emission test (TEOAE), with a threshold auditory brainstem response (ABR) recording undertaken on those who failed. The screen identified infants with a permanent congenital hearing impairment (PCHI) averaging 40 dBnHL or worse in the best ear. Those with less impairment were also ascertained. The positive predictive value (PPV) of the ABR test and measures of delay between identification and eventual diagnosis were analysed. RESULTS: A targeted PCHI was found in 1.18/1000 neonates. The PPV of the ABR for confirming a targeted PCHI was 100% when the ABR threshold was >/= 80 dBnHL. Nine of 11 infants with this threshold had severe or profound permanent deafness. The delay from ABR to audiological certainty was about 1 month-diagnosis was confirmed around 3 months. There was uncertainty when the ABR was 40-80 dBnHL. The PPV was 60% and 8% when the ABR thresholds were 70 dBnHL and 50 dBnHL, respectively. 85 of 111 infants with ABR thresholds in this range had a temporary conductive impairment. Their early diagnosis depended upon the type and degree of hearing impairment and diagnosis was delayed to about 8 months in these infants. CONCLUSIONS: Hearing impairments identified by universal screening are delayed in all but those with severe or profound bilateral PCHI. This delay can be reduced by applying in early infancy a battery of audiological tests and requires further exploration.  (+info)

Otolaryngological findings in congenital nasolacrimal duct obstruction and implications for prognosis. (2/154)

AIM: To investigate otolaryngological abnormalities associated with congenital nasolacrimal duct obstruction (CNLDO) and their effect on the prognosis. METHODS: 65 consecutive cases of CNLDO were followed up with routine otorhinolaryngological examination with tympanometry. RESULTS: Otitis media with effusion (OME) and uvula bifida were detected in 44.6% and 9.2% of the children, respectively. Medical treatment and probing were less effective in patients with OME (p<0. 05). CONCLUSIONS: OME and uvula bifida are significant anomalies associated with CNLDO and the former has a marked effect on the prognosis. This finding may help to determine the patients who will need further treatment after massage and probing.  (+info)

Tympanometry for diagnosis and treatment of otitis media in general practice. (3/154)

OBJECTIVE: The aim of this study was to evaluate the role of tympanometry for diagnosis, treatment and follow-up of otitis media in general practice. METHODS: The results from otoscopy performed by 40 physicians in general practice in Vejle County, Denmark were combined with the clinical condition and this was recorded as the preliminary decision about diagnosis, treatment and follow-up. Subsequently, tympanometry was performed in 3176 children aged between 1 month and 16 years; a total of 6352 tympanometries. With this added knowledge, a final decision about diagnosis, treatment and follow-up was recorded. The practitioners were trained in performing tympanometry including the interpretation of the results. Simultaneously, they were involved in the establishment of guidelines for diagnosis, treatment and follow-up of otitis media in general practice. The main outcome measures were changes between preliminary and final decisions about diagnoses, treatments and follow-up regimens. RESULTS: Tympanometry was performed successfully in 87.7% of the children, and in 26.4% changes in diagnoses were found. However, tympanometry did not influence the distributions of the main outcome measures in the sample as a whole. Uncomplicated cases were checked in general practice and referrals to specialists were not increased. CONCLUSION: Tympanometry can be performed successfully in general practice after appropriate instruction. In 26.4% of children, the diagnoses were changed, which may result in more appropriate treatment and follow-up. Tympanometry is a clinically relevant supplement to the examination of a child in general practice.  (+info)

Behaviour and developmental effects of otitis media with effusion into the teens. (4/154)

OBJECTIVE: To examine whether behavioural or cognitive sequelae of otitis media with effusion (OME) continue into late childhood and the early teens (11-18 years). SETTING: Data from a large multipurpose birth cohort study: the Dunedin multidisciplinary health and development study. PARTICIPANTS: Around 1000 children from the study. The main independent variable of interest was otological status of the child up to age 9. MAIN OUTCOME MEASURES: Parent and teacher rated behaviour problems, including antisocial, neurotic, hyperactive, and inattentive behaviours, and tests of academic achievement including intelligence quotient (IQ), reading, and spelling were available in a high proportion of the cohort at ages 11 to 18 years. RESULTS: After adjustments for covariates such as socioeconomic status, hyperactive and inattentive behaviour problems were evident as late as 15 years, and lower IQ associated with OME remained significant to 13 years. The largest effects were observed for deficits in reading ability between 11 and 18 years. CONCLUSIONS: No previous study considering behaviour problems as an outcome has followed children long enough to determine whether some of the early sequelae of OME are still present in the early to late teens. Some developmental sequelae of OME, particularly deficits in reading ability, can persist into late childhood and the early teens.  (+info)

Does early detection of otitis media with effusion prevent delayed language development? (5/154)

OBJECTIVE: To consider whether earlier detection of otitis media with effusion (OME) in asymptomatic children in the first 4 years of life prevents delayed language development. METHODS: MEDLINE and other databases were searched and relevant references from articles reviewed. Critical appraisal and consensus development were in accordance with the methods of the Canadian Task Force on Preventive Health Care. RESULTS: No randomised controlled trials assessing the overall screening for OME and early intervention to prevent delay in acquiring language were identified, although one trial evaluated treatment in a screened population and found no benefit. The "analytic pathway" approach was therefore used, where evidence is evaluated for individual steps in a screening process. The evidence supporting the use of tools for early detection such as tympanometry, microtympanometry, acoustic reflectometry, and pneumatic otoscopy in the first 4 years of life is unclear. Some treatments (mucolytics, antibiotics, steroids) resulted in the short term resolution of effusions as measured by tympanometry. Ventilation tubes resolved effusions and improved hearing. Ventilation tubes in children with hearing loss associated with OME benefited children in the short term, but after 18 months there was no difference in comparison with those assigned to watchful waiting. Most prospective cohort studies that evaluated the association between OME and language development lacked adequate measurement of exposure or outcome, or suffered from attrition bias. Findings with regard to the association were inconsistent. CONCLUSIONS: There is insufficient evidence to support attempts at early detection of OME in the first 4 years of life in the asymptomatic child to prevent delayed language development.  (+info)

Auditory system: Peripheral nonlinearity and central additivity, as revealed in the human stapedius-muscle reflex. (6/154)

Human stapedius-muscle contractions in response to 3-kHz, 20-msec tone bursts were determined indirectly by measuring the associated acoustic-impedance changes at the tympanic membrane with an acoustic bridge. The measurement was possible because the bridge practically eliminates the effect of the ear-canal air volume interposed between the tympanic membrane and the tip of the measuring tube. By using burst pairs, temporal additivity of the muscle responses was demonstrated both when the stimulus bursts were presented contralaterally to the measured impedance changes and when the first burst was presented ipsilaterally. The summation time constant was on the order of 200 msec, much longer than the twitch time constant of the muscle fibers. Therefore, the summation had to take place in a nucleus preceding the stapedius muscle. The magnitude of the muscle response obeyed a compressive function paralleling the loudness function up to sound pressure levels of at least 120 dB.  (+info)

Practical screening priorities for hearing impairment among children in developing countries. (7/154)

Routine screening for hearing impairment in childhood is now widespread in industrial countries, although there is considerable controversy over the most efficient techniques and procedures. In most developing countries, however, routine screening programmes for hearing impairment do not currently exist. The problems involved in implementing screening programmes in developing and industrial countries are very different, and in selecting screening procedures for a particular population the following factors have to be taken into consideration: the environmental test conditions; the availability of resources for equipment and the training of testers; the local attitudes towards disability; the level of hearing impairment that may cause handicaps; and the major types of pathology causing hearing impairment. We suggest that in developing countries children should be screened at school entry using a simple field audiometer and that the external ear be inspected for the presence of a discharge. There is an urgent need to develop reliable and simple screening procedures for infants and young children; where possible, all children should be screened for severe or significant hearing impairment before the age of 2 years. No screening should, however, be implemented until appropriate follow-up services are available.  (+info)

Impedance analysis of the organ of corti with magnetically actuated probes. (8/154)

An innovative method is presented to measure the mechanical driving point impedance of biological structures up to at least 40 kHz. The technique employs an atomic force cantilever with a ferromagnetic coating and an external magnetic field to apply a calibrated force to the cantilever. Measurement of the resulting cantilever velocity using a laser Doppler vibrometer yields the impedance. A key feature of the method is that it permits measurements for biological tissue in physiological solutions. The method was applied to measure the point impedance of the organ of Corti in situ, to elucidate the biophysical basis of cochlear amplification. The basilar membrane was mechanically clamped at its tympanic surface and the measurements conducted at different radial positions on the reticular lamina. The tectorial membrane was removed. The impedance was described by a generalized Voigt-Kelvin viscoelastic model, in which the stiffness was real-valued and independent of frequency, but the viscosity was complex-valued with positive real part, which was dependent on frequency and negative imaginary part, which was independent of frequency. There was no evidence for an inertial component. The magnitude of the impedance was greatest at the tunnel of Corti, and decreased monotonically in each of the radial directions. In the absence of inertia, the mechanical load on the outer hair cells causes their electromotile displacement responses to be reduced by only 10-fold over the entire range of auditory frequencies.  (+info)

Learn about different techniques for representing a perforate and a method that makes it simple to compute its acoustic transfer impedance.
The present study reports densities (ρ), viscosities (η) and ultrasonic speeds (U) of pure dioxane (DOX), anisole (ANS), toluene (TOL) and ethylbenzene (ETB) and their binary liquid mixtures over the entire composition range at 293, 298, 303, 308 and 313 K. From the experimental data excess molar volume (VmE), excess intermolecular free length (LfE), excess adiabatic compressibility (βE) and excess acoustic impedance (ZE) have been computed. The excess values were correlated using Redlitch-Kister polynomial equation to obtain their coefficients and standard deviations (σ). With increase in temperature, the binary mixture of DOX+ANS shows larger deviations in βE, LfE and smaller deviations in ZE, VmE. These results suggest that ANS has strong molecular interactions with DOX than ETB and TOL.
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Allocation was well concealed, and followup rates were high (95%). Participants provided outcome data with self completed questionnaires, and the researchers who collected and entered the data were blind to the participants allocation status. At the paediatric assessments, some parents talked about their childcare arrangements, and so we cannot exclude the possibility of bias in the assessment of child development. However, such a bias is unlikely for the results for otitis media, as the two paediatricians examined the printed tympanograms without any identifying information. Although the ratio of intervention to control families varied over the course of recruitment, this is unlikely to have resulted in bias since the availability of daycare places is not expected to have been related to any outcome variable.. The main study weakness is the lack of power because of our inability to achieve a sufficientlylarge sample size. This was an opportunistic evaluation of an anti-poverty strategy in a ...
Program to perform acoustic simulation using lumped parameter analysis. Also measures acoustical impedance such as acoustical flow impedance and acoustical surface impedance
An acoustic well logging tool is shown having a transmitter section and a receiver section spaced apart by a semi-rigid housing. The semi-rigid housing includes a number of rigid tubular members which are joined by interlocking lobes which permit relative movement between the tubular members but which prevent the separation thereof. Gaps between the interlocking lobes are filled with a connecting material which differs significantly in acoustic impedance from the material of the remainder of the housing, whereby acoustic energy passing from the transmitter section along the body of the tool is delayed and attenuated.
The book is concerned with properties such as density, refractive index, acoustic impedance and electrical conductivities of hydrocarbon substances.
Perturbation bandwidth effects on admittance of a typical subject. The magnitude of the admittance is shown for FT (left), RT (middle) and PT (right) at all per
This set goes with 1 tympanometry probe and 1visual inspection probe to enable you to do OAE testing on both ears simultaneously. Be up to 4 times faster than competition!. ...
Definition of acoustic reflex threshold in the Financial Dictionary - by Free online English dictionary and encyclopedia. What is acoustic reflex threshold? Meaning of acoustic reflex threshold as a finance term. What does acoustic reflex threshold mean in finance?
Paediatric tympanometry test, middle ear problem and hearing loss test done under best hearing consultant to detect problem in middle and outer ear, speech and hearing clinic in Delhi, Noida, Gurugram and Patna.
Context: Blood pressure tracking has suggested that the difference in blood pressure between women and men begins to manifest during the adolescent period. It is therefore postulated that sex-related cardiac structural and functional differences that could predict future events may exist in the heart of offspring of parents with hypertension. Aims: This study aimed at evaluating the effects of sex difference on the heart of offspring of parents with hypertension. Settings and Design: Cross-sectional study. Participants and Methods: A group of offspring of parents with hypertension aged between 15 and 25 years were recruited for the study if they had normal blood pressure and gave consent. They had clinical, electrocardiography, and echocardiographic assessments. Results: Sixty-five participants consisting of 47 males and 18 females participated in the study. Mean systolic blood pressure was higher (P = 0.001) in the males compared with the females but the diastolic blood pressure was similar ...
With every hearing test, our audiologist runs a tympanogram. This measures the mobility of the eardrum and can give an indicator of middle ear health. A nice, healthy middle ear gives a "Type A" tympanogram, with a nice peak to indicate the eardrum is functioning properly. I actually only have one tympanogram with this configuration- this example is from Nolans right ear during a relatively fluid-free period of time. This was also shortly after his second PE tube fell out of the right ear ...
Ultrasonic testing uses the same principle as is used in naval SONAR and fish finders. Ultra-high frequency sound is introduced into the part being inspected and if the sound hits a material with a different acoustic impedance (density and acoustic velocity), some of the sound will reflect back to the sending unit and can be presented on a visual display. By knowing the speed of the sound through the part (the acoustic velocity) and the time required for the sound to return to the sending unit, the distance to the reflector (the indication with the different acoustic impedance) can be determined. The most common sound frequencies used in UT are between 1.0 and 10.0 MHz, which are too high to be heard and do not travel through air. The lower frequencies have greater penetrating power but less sensitivity (the ability to "see" small indications), while the higher frequencies dont penetrate as deeply but can detect smaller indications.. The two most commonly used types of sound waves used in ...
Ultrasonic testing uses the same principle as is used in naval SONAR and fish finders. Ultra-high frequency sound is introduced into the part being inspected and if the sound hits a material with a different acoustic impedance (density and acoustic velocity), some of the sound will reflect back to the sending unit and can be presented on a visual display. By knowing the speed of the sound through the part (the acoustic velocity) and the time required for the sound to return to the sending unit, the distance to the reflector (the indication with the different acoustic impedance) can be determined. The most common sound frequencies used in UT are between 1.0 and 10.0 MHz, which are too high to be heard and do not travel through air. The lower frequencies have greater penetrating power but less sensitivity (the ability to "see" small indications), while the higher frequencies dont penetrate as deeply but can detect smaller indications.. The two most commonly used types of sound waves used in ...
An ultrasonic probe particularly suitable for ultrasonic diagnostic equipments of the electronic scanning type is made up of a multiplicity of piezoelectric transducer elements, each in the shape of a rectangular plate with electrode films coated on both sides, arranged in a row at intervals and an acoustic impedance matching layer placed on the row of the transducer elements. The width-to-thickness ratio of each piezoelectric plate takes a value not greater than 0.8 and preferably between 0.4 and 0.7 so that the plate can vibrate in width expansion mode. It is highly preferable that the impedance matching layer has a laminated structure given by two layers which are different in acoustic impedance of the respective materials and individually have definite thicknesses.
In order to efficiently and effectively address noise problems, it is important to have the right type and combination of technology to deliver the expected level of accuracy for the job at hand, depending on the frequency range or problem complexity. The acoustic simulation solutions cover Acoustic Transfer Vector (ATV), Automatically Matched Layer (AML), aero-acoustics, ray-acoustics, random vibro-acoustics as well as uncoupled to fully coupled acoustic problems. The Statistical Energy Analsysis (SEA) capabilities embedded into the SEA+ product allow to extend the frequency range to high frequencies. A unique capability converts automatically FEM models into SEA models, making it very convenient to analyse the full frequency spectrum.. End-to-end process support. With the best-in-class vibro-acoustic solvers, interfaces to leading CFD and electro-magnetic codes, LMS Virtual.Lab Acoustics is an ideal platform to address the acoustic multidisciplinary problem and optimize the sound performance. ...
MARATHON, N.Y. - While most modern farmers work their fields accompanied by the rumble of a trusty tractor, sheep farmer Donn Hewes labours to the faint jingling of harnesses in rhythm with the hoofbe...
Simplified schematic of the wireless energy transfer system in free space. Yu et al. Click to enlarge. A Stanford University research team is designing a high-efficiency wireless charging system using magnetic resonance coupling (earlier post) to wirelessly transmit large electric currents between metal coils placed several feet apart. The long-term...
A system and method senses an in-vivo lumen using ultrasonic elements typically arranged in a ring or other similar structure. Position information may be collected. A set of reflectance data may be collected and used to form an image or representation of the lumen. In one example, the data is collected by an in-vivo autonomous capsule. Additionally, ultrasonic elements may be arranged in order to receive a mechanical characteristic of the tissue (e.g., acoustic impedance) rather than an image or representation.
The Attitude not only displays this information, but allows you to adjust the power control settings with a touch of a button. The Power Edge Juice is a plug in module that installs under the hood in less than 10 minutes. It features five power levels with power gains from 40-125 hp and torque gains from 150-300 ft lbs. The Juice module communicates on the CAN-Bus data stream, from this data it receives vital engine, transmission, and fuel system information. This information provides smooth precise power delivery and power curves that are custom tailored rather than offset from stock. The Power Edge Juice improves throttle response, drivability, and towing performance. The module is weatherproof and mounts under the hood. ...
NEW - NOW AVAILABLE IN 30T - Using unique countersunk spacers and M5 Torx bolts OneUp has developed the only 30T oval ring that works with all 104BCD cranks. Our Oval design has 3 main benefits; traction, traction and more traction. Forget any of the power gain claims that youve heard from the road side of the sport.
Now entering its 43rd season, the TAKÁCS QUARTET is renowned for the vitality of its interpretations, "revealing the familiar as unfamiliar, making the most traditional works feel radical once more ...
Anderson Banihirwe from NCAR gave this talk at SciPy 2019. "This talk demonstrates how to use Dask and Jupyter on large high-performance computing (HPC) systems to scale and accelerate large interactive data analysis tasks - effectively turning HPC systems into interactive big-data platforms. We will introduce dask-jobqueue which allows users to seamlessly deploy and scale dask on HPC clusters that use a variety of job queuing systems such as PBS, Slurm, SGE, and LSF. We will also introduce dask-mpi, a Python package that makes deploying Dask easy from within a distributed MPI environment.". ...
Pneumatic Otoscopy Kit, Diagnostic & Procedural Trainer- Partnering with the University of Virginia, Nasco also offers an exciting additional feature for the Life/form Diagnostic and Procedural Ear Trainer (LF01090U). While pneumatic otoscopy is indi
Facial nerve is the seventh paired cranial nerve. The main trunk of CN VII consists of motor fibers and the intermediate nerve which is a part of CN VII has parasympathet..
• The properties of pooled thick and thin middle ear effusions, from children with otitis media with effusion, were studied by viscometry. Mucus glycoproteins w
CRITIQUE: The book is an excellent for the resident, novice ENT physician, the audiologist and is a must for the Au.D. student in training. Even with the many advances in imaging, otoscopy remains the cornerstone in diagnosis of ear disease. Unfortunately, significant clinical experience in examining is required to become proficient in otoscopy. The beginning student or resident will find it helpful to study the text and illustrations carefully to build a better feel for the appearance of the ear in various conditions. The experienced audiologist will find this a useful reference text to consult after viewing questionable ear pathology in everyday practice. The index is well organized and appropriately detailed allowing for a quick and accurate reference. The bibliography is adequate but in no way an exhaustive list of classical or definitive articles of the various pathology. The authors make excellent use of illustrations but clinical history and most certainly audiological information is at ...
Synonyms for Acoustic reflex in Free Thesaurus. Antonyms for Acoustic reflex. 26 synonyms for reflex: automatic, spontaneous, instinctive, involuntary, impulsive, knee-jerk, unthinking, automatic, impulsive, instinctive, involuntary.... What are synonyms for Acoustic reflex?
NIH Toolbox Assessment of Neurological and Behavioral Function Validation of the NIH Toolbox in Rehabilitation Populations David Tulsky, PhD Supported by Unveiling the NIH Toolbox Bethesda, MD September
In this paper we demonstrate the use of the capillary pressure equilibrium theory (CPET) model to address the effects of partial saturation in order to estimate hydrocarbon saturation in a reservoir volume using acoustic impedances derived by seismic inversion. The data set used here has been donated by BHP Billiton, and is from an offshore oilfield called the Stybarrow field. The set comprises of a well with a 20-foot sandstone oil saturated pay section and 3D pre- and post-stack seismic volumes. Using the provided angle stacks and well log data, a statistical wavelet, and low impedance model, the final impedance model is computed. There are two final impedance models, derived from post-stack, and pre-stack data. The final impedance models are in agreement with one another at each of the well locations, with low impedance at the oil saturated well, and high impedance at the water saturated well. The corresponding CPET model is built based on the empirical porosity from the well log. The rock ...
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NOTE: Insufficient cleaning of the spark plug may lead to spark plug failure in a very short period of time. Clean the spark plug thoroughly to avoid problems later. Remember, if a spark plug is fouling its usually a result of engine side factors or incorrect heat range selection.. Performance gain after installing the plug: A common misconception is that changing spark plugs will result in a large power increase. In most cases, removing even seriously worn out spark plugs will only result in tiny power gains, typically about 1-2% of total engine output. This could be even less for computer-controlled vehicles, primarily because most newer vehicles have more powerful ignition systems and the vehicles computer can make adjustments so that vehicle operation is not affected by the resistance generated by the spark plug.. Many people think that simply supplying more spark to the firing tip can and will combust more fuel. What they dont understand is that most new fuel injected vehicles are ...
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The Theoretical Foundation and Applications of Equivalent Transmission-Path Model for Assessing Wideband Digital Transmission Characteristics in Nakagami-Rice Fading ...
ULTRA Series Cy®5 wideband fluorescence filter set designed to provide bright, high-contrast images of Cy®5-stained samples when illuminated with an LED light source. This filter set is also ideal for use with Spectrum Far Red, Alexa Fluor® 647, DRAQ5™, a
SaudiMac reports, that Apple has officially confirmed and outlined where their FaceTime video calling service isnt available. When looking at the chart, every country and carrier with a footmark of
A simple model of wideband HF noise/interference has been developed and used to simulate the noise/interference process. The… Expand ...
A 57 years old male patient who wore Hearing Aid unilaterally in left ear referred to our clinic to get Hearing Aid for his right ear [1,2]. In Otoscopy TM in right ear was normal but in left ear External ear Canal was full of wax (Cerumen) and Otoscopy was not possible [3]. Cerumen in left ear was probably produced because of wearing Hearing Aid with occluded ear mold [4]. Tympanometry was performed before referring patient for removing Cerumen. The result was Type A in right ear and Type B with ECV=5cc in left ear [2,5]. If Type B were false, ECV should be low but high ECV in left ear indicated perforation. Since large probe cuffs may increase ECV falsely Tympanometry was done again by changing rubber probe cuff for a better diagnosis.Result was not change and ECV with new cuff was still 5cc. After removing Cerumen by suction method vast central perforation was revealed in Otoscopy of left ear [6].. ...
Introduction Fatigue is an unstoppable outcome to any intense training session or period of training. We can define fatigue as any drop in motor output during a session. Do not mistake fatigue for only something an endurance athlete feels during a run; fatigue includes a reduction in bar speed, falling short of a prescribed rep range, or performance decrements during a session of General Physical Prepardeness (GPP). A drop in motor output is inevitable and even failure will always eventually occur, however, we do have the ability to delay fatigue. As powerlifters delaying fatigue allows us to increase our total training volume or even perform a greater number of reps at a higher percentage of our max, thus leading us to greater strength and power gains. The Problem To Be Addressed The noted drop in motor output occurs as Adenosine Triphosphate (ATP) is depleted and metabolites (H+ ions and therefore lactate) accumulate. As Hydrogen ion (H+) concentration increases due to the degradation of ATP, ...
On the basis of recent advances in auditory physiology, new tests of cochlear function have been developed using measures of otoacoustic emissions. In the present report, the clinical potential for each of the four basic emission types is examined. In addition, the practical advantages of examining the ear with two specific types of evoked emissions, transiently evoked and distortion-product otoacoustic emissions, are reviewed in detail. Finally, the future role of tests of otoacoustic emissions in the diagnosis of hearing impairment is discussed. The current view is that evoked emissions hold promise as an essential part of the clinical examination of the auditory system.. ...
Conductive hearing loss occurs when there is a problem in the inner ear. Learn about the causes and different treatment options of conductive hearing loss.
... occurs when there is a problem in the inner ear. Learn about the causes and different treatment options of conductive hearing loss.
... occurs when there is a problem in the inner ear. Learn about the causes and different treatment options of conductive hearing loss.
Middle Ear Effusion in Intensive Care Unit Patients at Al-Sadder Teaching Hospital in Al-Najaf City-Iraq (A Prospective Randomized Comparative Clinical Study)
Get exceptional Video Otoscopy services from highly experienced & loving pet care professionals in New Windsor, NY. Visit VCA Flannery Animal Hospital today.
I recently saw a patient with a diagnosis of severe CS arthritis with main complaints of numbness/tingling of her UE and ringing in her ears. It appears that the intensity of the ringing in her ears is positively affected by the supine active sacro spheno flexion activity. After this technique, the ringing is less intense. She is now beginning to be able to control it with good diaphragmatic breathing in appropriate posture. Can you help me better understand the physiology/anatomy of why this may be happening? The Supine Active Sacro-Spheno Flexion technique restores OA extension on the right, repositions the sphenoid in sagittal neutrality and in general, places the sphenoid in a state of flexion. The right temporal bone is then pulled into ER (external rotation) via the right styloid muscles. So, in essence the tensor tympanics in the temporal bones and the tensor veli palatins are re-set or repositioned to allow for normal malleus and inner ear function. Thanks for the question ...
Conductive hearing loss means sound cannot reach the inner ear due to a physical issue. Learn more about why this can happen and how to treat it.
Paediatric Audiometry It is often more difficult to obtain accurate hearing thresholds at all frequencies when testing children under four years of age. Tympanometry and otoacoustic emissions are often performed prior to any subjective form of testing. Then, depending on the developmental age of the child, either distraction testing, performance testing (visual re-inforced
In depth analysis of Otoacoustic Emissions Market is a crucial thing for various stakeholders like investors, CEOs, traders, suppliers and others. The Otoa
Acoustic impedance of the embouchure hole appears the most critical parameter. Critical variables affecting this acoustic ... Tests with experienced professional flutists and listeners and one model of a flute made by Muramatsu from 7 different ... "Acoustic impedance of the flute". Flute acoustics: an introduction. "Curved Head Student Flute by Gear4music". Gear4music. 2016 ... However, small deviations from the objective 'mechanical' pitch (which is related to acoustic impedance of a given fingering) ...
... is made of a material having a low acoustic impedance and has a sufficiently thick wall to ensure structural stability. Close- ... In the proposed test, test parameters will be sensitivity, background noise, signal fidelity (harmonic distortion), and ... In music, acoustic waveguide methods, such as a large pipe organ or, for reproduction, exotic loudspeaker designs such as ... In the second concert, the pieces that were to carry a 17 Hz undertone were swapped so that test results would not focus on any ...
It was found that a layer with high acoustic impedance with a backing of a softer, low acoustic impedance layer (such as low ... Bass et al., 2006, Comparative testing of effectiveness of different helmet/shield designs at reducing head acceleration due to ... similar to the NIJ standards that are widely used to test and compare body armor or materials used to stop ballistic threats. ... it was also shown that it is important to understand the frequency content of the applied blast wave and to experimentally test ...
... noise and vibration testing and structural dynamics testing. Brüel & Kjær offers products that cover a wide range of acoustic ... and acoustic panel in-situ impedance measurement) Brüel & Kjær also supplies in-flight engine monitoring with flight-certified ... Other systems have tested Astrium's satellite prior to launch, and performed qualification and acceptance testing, such as the ... These ensure the quality of new lighter material applications by modal testing and improving the quality and test efficiency in ...
CSSI transforms seismic data to a pseudo-acoustic impedance log at every trace. Acoustic impedance is used to produce more ... which can then be narrowed through testing for best fit against various measurements (including production data). An example of ... The inversion results in acoustic impedance (AI), which is the product of rock density and p-wave velocity. Unlike seismic ... A good (CSSI) algorithm will produce four high-quality acoustic impedance volumes from full or post-stack seismic data: full- ...
... the use of some type of acoustic coupling medium in order to efficiently transmit the energy from the sensor to the test ... piezoelectric transducer can produce frequencies in the MHz that can easily propagate through even high acoustic impedance ... Non-contact ultrasound (NCU) is a method of non-destructive testing where ultrasound is generated and used to test materials ... However in non-contact ultrasound, ambient air is the only acoustic coupling medium. An electromagnetic acoustic transducer ( ...
Moreover, the acoustic performance is linked to the acoustic impedance which can be measured with one of the following ... The acoustic liners' performance can be verified in dedicated experimental test rigs, by means of virtual prototypes or by ... Effects of liner geometry on acoustic impedance. AIAA Paper, 2446, 2002. Dean, P. D.,An In-Situ Method of Wall Acoustic ... Moreover, the in-situ method is the only one able to measure the impedance directly on full scale acoustic liners. Murray, P., ...
Most of the time, the stapedius reflex is tested with tympanometry. The contraction of the stapedius muscle stiffens the middle ... 267-9. ISBN 0-07-285293-3. "Impedance Audiometry". MedScape. W. Niemeyer (1971). "Relations between the Discomfort Level and ... the sound used to trigger the acoustic reflex). For most animals, the acoustic reflex is the contraction of both middle ear ... The acoustic reflex threshold (ART) is the sound pressure level (SPL) from which a sound stimulus with a given frequency will ...
First successful industrial applications of acoustic metamaterials are tested for aircraft insulations. Since the acoustic ... Based on Newton's observation we can conclude that a key factor for acoustic band-gap engineering is impedance mismatch between ... High-resolution acoustic imaging techniques are the essential tools for nondestructive testing and medical screening. However, ... We can exploit this concept with periodic (and handcrafted) arrangements of impedance mismatched elements to affect acoustic ...
The test is carried out by generating an acoustic pulse from a speaker or spark source and this sound pulse is transmitted to ... is reflected back to a microphone and this reflection is generated according to the changes in the local acoustic impedance ... Acoustic Rhinometry is a diagnostic measurement of the nose and the nasal cavity through acoustic reflections. It can be used ... O, Hilberg; AC, Jackson; DL, Swift; OF, Pedersen (1989). "Acoustic Rhinomtry: Evaluation of nasal cavity geometry by acoustic ...
TEST OF PROJECT ARTEMIS ACOUSTIC SOURCE PROJECT ARTEMIS ACOUSTIC SOURCE - ACOUSTIC TEST PROCEDURE Project ARTEMIS High Power ... Analysis of Transducer-Impedance Variations on the Amplifier Operation. Project ARTEMIS High-Power Acoustic Source. PROJECT ... High Power Acoustic Source. Interim Report on Acoustic Performance Project ARTEMIS. High Power Acoustic Source. Interim Report ... High Power Acoustic Source. PROJECT ARTEMIS ACOUSTIC SOURCE SUMMARY REPORT High-Data-Rate System for the ARTEMIS Long-Range ...
The Acoustic Test Tank is equipped with the instrumentation required for determining the acoustic characteristics of sonar ... devices designed for frequency response calibrations, radiation pattern plots, and impedance and admittance characterizations. ... Laboratory which houses an array of tanks including an Acoustic Reverberant Tank and an Acoustic Test Tank for acoustic ... ARL operates the Advanced Nuclear Fuel Test Facility (ANFTF) which is a Westinghouse-funded facility to test advanced power ...
Common causes of echo include impedance mismatches in analog circuitry and acoustic coupling of the transmit and receive signal ... "Performance and Stress Testing of SIP Servers, Clients and IP Networks". StarTrinity. 2016-08-13. "Testing Voice over IP (VolP ... The metrics are determined by VoIP performance testing and monitoring. A VoIP media gateway controller (aka Class 5 Softswitch ... "Methodology for SIP Infrastructure Performance Testing" (PDF). Miroslav Voznak, Jan Rozhon. 2016-08-14. "Voice over IP (VoIP) ...
... which reflect the sound due to mismatched acoustic impedance. Brown note Sone (a unit of loudness of sound) Sound pressure ... Tests performed on mice show the threshold for both lung and liver damage occurs at about 184 dB. Damage increases rapidly as ... A long-range acoustic device has been used by the crew of the cruise ship Seabourn Spirit to deter pirates who chased and ... A similar system is called a "magnetic acoustic device." 'Mobile' sonic devices have been used in the United Kingdom to deter ...
The acoustic (or seismic) impedance, Z, is defined by the equation: Z = V ρ {\displaystyle Z=V\rho \ } , where V is the seismic ... This led to another variation on the NATS survey type, the wide-azimuth towed streamer (or WAZ or WATS) and was first tested on ... Hydrocarbon exploration - used by the hydrocarbon industry to provide a high resolution map of acoustic impedance contrasts at ... Seismic waves are mechanical perturbations that travel in the Earth at a speed governed by the acoustic impedance of the medium ...
These boards were wired at the factory, tested and packaged with the unassembled chassis. It remained only for the consumer to ... The resistant venting action lowered the "Q" of the system and reduced impedance variation near resonance in the A-Series ... whose acoustic resistance is very carefully controlled. ... tested circuit boards that only required the customer to wire ... which generally required the purchaser to assemble and test the PC boards themselves, a relatively precise and time-consuming ...
... allowing the acoustic transfer impedance Z a c {\displaystyle Z_{ac}} to be easily modelled. One of the microphones is then ... This service is offered by some microphone manufacturers and by independent testing laboratories. Microphone calibration by ... and the acoustical transfer impedance equals the electrical transfer impedance. Z i j = U j I i = M i Z a c M j {\displaystyle ... is determined during the calibration procedure by measuring the current and voltage and the acoustic transfer impedance depends ...
Brånemark sought an acoustic way to evaluate osseointegration. A patient with implants in the jaws was fitted with a bone ... When tested, the patient experienced very loud sound even at low stimulation levels, indicating sound could propagate very well ... The hearing instrument is impedance-matched. Osseointegration has been defined as the direct contact between living bone and an ...
Anechoic Chamber: another acoustic test facility Echo chamber: a reverberation room used for music recording Electromagnetic ... The change of impedance (compared to the air) these surfaces present to incident sound is so large that virtually all of the ... an electromagnetic environment mainly for Electromagnetic Compatibility testing ISO Standard for Measurement of Acoustic ... additional acoustic diffusers are often used to create more reflecting surfaces and further encourage even distribution of any ...
However, due to the general equality in acoustic impedance for many types of structures in the breast ultrasound imaging ... DATG is not a test that directly substitutes for other tests, but stands in relation to them as a technique that provides a ... The angiothermography is not a test that substitutes for other tests, but stands in relation to them as a technique that gives ... As such, it has been most successfully employed in combination with other tests to improve the quality of the diagnosis. ...
... hearing tests MeSH E01.370.382.375.050 --- acoustic impedance tests MeSH E01.370.382.375.060 --- audiometry MeSH E01.370. ... impedance MeSH E01.370.370.610.610.200 --- cardiography, impedance MeSH E01.370.370.750 --- tilt-table test MeSH E01.370. ... intradermal tests MeSH E01.370.750.300.400 --- kveim test MeSH E01.370.750.300.750 --- skin test end-point titration MeSH ... intradermal tests MeSH E01.450.495.750.300.540 --- kveim test MeSH E01.450.495.750.300.750 --- skin test end-point titration ...
In an acoustic set, the parts act like narrow pass-band filters, and their central frequencies should be perfectly aligned to ... Impedance analyzers can be used as advanced horn analyzers, but are not usually a cost-effective alternative for everyday ... A digital horn analyzer performs a frequency sweep while monitoring the current flowing through the device under test, in order ... The anti-resonance is the frequency at which the current encounters maximum impedance, and the resonance is the frequency of ...
Acoustic impedance varies by rock type and can therefore be correlated to rock properties using rock physics relationships ... These blind-well mode inversions test the reliability of the constrained inversion and remove potential biased. This ... Seismic surveys measure acoustic impedance contrasts between rock layers. As different geologic structures are encountered, the ... Geostatistical inversion simultaneously inverts for impedance and discrete properties types, and other petrophysical properties ...
This acoustic impedance log is combined with the velocity data to generate a reflection coefficient series in time. This series ... It can also be used either to test possible interpretation models for 2D and 3D seismic data or to model the response of the ... This information is then used to calculate the variation in acoustic impedance down the well bore using the Zoeppritz equations ... It may also be used to test out different geometries of structures such as salt diapirs, to see which gives the best match to ...
TMD fails to provide accurate estimates of ICP mostly because the acoustic impedance and its changes due to the acoustic reflex ... OAE is used in clinical practice to test for hearing deficits in babies and children who are too young to cooperate. The ... depend not only on the initial position of stapes but also on numerous other factors that affect the acoustic impedance ( ... multivariate methods have been proposed that derive ICP by combining the transit times with measured acoustic impedance, ...
The main reason for this is the difficulty of achieving proper impedance matching between the acoustic impedance of the drive ... as it also depends on the directivity of the driver being tested and the acoustic environment in front of the actual ... This improves the acoustic-electro/mechanical impedance match between the driver and ambient air, increasing efficiency, and ... The horn also improves impedance matching between the voice and the air, which produces more acoustic power for a given speaker ...
Acoustic Impedance Tests* / methods * Adult * Ear, Middle * Hearing Loss, Conductive / etiology * Humans ... The most remarkable effects were conductive hearing loss at lower frequencies and an increase in middle-ear impedance. ...
Acoustic impedance tests. Additional relevant MeSH terms: Hearing Loss. Deafness. Otitis Media. Otitis Media with Effusion. ... tests of absorbance for improved sensitivity in the assessment of middle-ear function including acoustic reflex testing. The ... Middle ear test [ Time Frame: Assessed at time of enrollment ]. The standard clinical middle ear test, 226 Hz tympanometry, and ... Wideband otoacoustic emission test [ Time Frame: Assessed at time of enrollment ]. An otoacoustic emission test assessed using ...
Measured by acoustic impedance measurement. *Changes in vestibular functions [ Time Frame: Up to 4 weeks ]. Measured by ... Clinical and Genetic Testing of Patients With Usher Syndrome. The safety and scientific validity of this study is the ... MedlinePlus related topics: Genetic Testing Usher Syndrome Genetic and Rare Diseases Information Center resources: Retinitis ... Measured by electronic audiometry (ASSR test). *Changes in efficient sound transmission in the middle ear [ Time Frame: Up to 4 ...
The secondary purpose of this test is to evaluate acoustic reflex pathways, which include cranial nerves (CN) VII and VIII and ... The primary purpose of impedance audiometry is to determine the status of the tympanic membrane and middle ear via tympanometry ... Acoustic immittance tests. The following tests are included in the category acoustic immittance tests:. * Tympanometry (most ... Acoustic reflex decay test. The acoustic reflex decay test is used to assess the integrity of CN VIII. ...
Chest electrical impedance tomography (EIT) is currently applied in neonatal and paediatric patients mainly within clinical ... Acoustic Impedance Tests. Objective tests of middle ear function based on the difficulty (impedance) or ease (admittance) of ... These include static impedance and dynamic impedance (i.e., tympanometry and impedance tests in conjunction with intra-aural ... Cardiography, Impedance. A type of impedance plethysmography in which bioelectrical impedance is measured between electrodes ...
Acoustic Impedance Tests. Audiometry. Cochlea / abnormalities. Diagnosis, Differential. Ear / abnormalities*. Ear Ossicles / ...
Acoustic Impedance Tests. Adolescent. Diagnosis, Differential. Ear, Middle / physiopathology. Eustachian Tube / physiopathology ...
Acoustic impedance tests. Acquired immunodeficiency syndrome. Audiometry. Auditory evoked potentials. Brainstem auditory evoked ... acoustic reflexes, otoacoustic emissions, otoacoustic emissions suppression, and brainstem auditory evoked potential; it was ...
Additional testing is often necessary.. Acoustic Immittance (also called Tympanometry or Impedance) A test that helps determine ... This test does not show whether the hearing is normal.. Todd​​lers. Evaluation of hearing may include the tests mentioned above ... This test is painless and takes approximately two hours. The test is either done in natural sleep (called an unsedated ABR) or ... This hearing test is typically done for infants over six months of age. This test takes advantage of a babys natural head turn ...
Test of single degree of freedom acoustic treatment impedance models for multimodal acoustic propagation in duct with flow. ... What vestibular tests to choose in symptomatic patients after a cochlear implant? A systematic review and meta-analysis. ...
Acoustic impedance testing including tympanometry and acoustic reflexes. · Speech Audiometry. · Evoked auditory assessment ... Balance Assessment including VNG, caloric and sway testing. · Rehabilitation of hearing loss including the fitting and ... The students will develop their testing techniques within Orthoptics as well as having an overview of a working Hospital Eye ...
... paired t test). Acoustic impedance increased significantly in the corneal stiffening group after treatment (P , 0.001, paired t ... Z w is the acoustic impedance of the coupling media (i.e., saline or aqueous humor), and Z c is the acoustic impedance of the ... two sample t test). No significant change in acoustic impedance was found in the control group after PBS treatment (P = 0.10, ... between Tono-Pen readings and acoustic impedance were smaller than the corresponding slopes between GAT and acoustic impedance ...
Acoustic compliance is measured under conditions of tympanometry but the tympanometry facility is disabled during displacement ... Preferably eardrum displacement is used as a baseline measure and acoustic compliance measurement records short-term variation ... Either or both of the displacement of the eardrum when the stapedius muscle is stimulated or the aural acoustic compliance of ... Electro-acoustic impedance bridges. US4289143 *. Jan 9, 1980. Sep 15, 1981. Cselt Centro Studi E Laboratori Telecomunicazioni S ...
The dime adds acoustic impedance which would reduce the speed and efficiency of the dissipation of the vibrations. Now if there ... Thats what Id do because it should be a pretty straight forward test. ...
Test for the middle ear is further segmented into tympanometry tests, acoustic reflex measures, and static acoustic impedance. ... On the basis of the test, the market is segmented into a test for middle ear, pure-tone test, and speech reception threshold ... test (SRT), most comfortable listening level test (MCL), uncomfortable loudness level test (UCL), speech discrimination test, ... Pure-tone test is further segmented into visual reinforcement audiometry, and conditioned play audiometry. ...
... acoustic impedance explanation free. What is acoustic impedance? Meaning of acoustic impedance medical term. What does acoustic ... Looking for online definition of acoustic impedance in the Medical Dictionary? ... The acoustic impedance of bone may be nearly five times as great as that of blood. Testing middle ear acoustic impedance is ... acoustic impedance at normal incidence of fluids, acoustic impedance at oblique incidence in fluids, the Biot theory of sound ...
This standard provides specifications for instruments designed to measure acoustic impedance, acoustic admittance, or both ... The book addresses criteria for selection of pure tone and speech tests, guidelines for test administration, testing of hearing ... American National Standard Specifications for Instruments to Measure Aural Acoustic Impedance and Admittance (Aural Acoustic ... The noise test signal specified herein has been employed by the National Bureau of Standards for over 20 years in testing ...
... using electroacoustic instrumentation and acoustic impedance equipment; to plan, conduct, habilitative and rehabilitative ... of audiometric testing protocols and test interpretations; of hearing aids and hearing aid evaluation techniques; and of aural ... of audiometric testing protocols and test interpretations; of hearing aids and hearing aid evaluation techniques; and of aural ... using electroacoustic instrumentation and acoustic impedance equipment; to plan, conduct, habilitative and rehabilitative ...
Acoustic impedance. The ratio of the complex amplitude of spatially averaged acoustic pressure over a surface to the complex ... Acoustic emission. A method of nondestructive testing and materials characterization that uses mechanical waves moving through ... Acoustic radiation pressure. The net pressure exerted on a surface or interface by an acoustic wave. One might presume that the ... Acoustic interferometer. An instrument that is sensitive to the interference of two or more acoustic waves. It provides ...
Acoustic impedance. The ratio of the complex amplitude of spatially averaged acoustic pressure over a surface to the complex ... Acoustic emission. A method of nondestructive testing and materials characterization that uses mechanical waves moving through ... Acoustic radiation pressure. The net pressure exerted on a surface or interface by an acoustic wave. One might presume that the ... The condition for which the impedance of a given electric, acoustic, or dynamic system is very high, approaching infinity. In ...
Brooks, D. N. The role of the acoustic impedance bridge in impedance screening. Scandinavian Audiology,1974, 3,99-.104.Google ... Anderson, H., Barr, B., Wedenberg, E. The early detection of acoustic tumors by the stapedius reflex test. In G. Wolstenholme J ... Harper, A. Acoustic impedance as an aid to diagnosis in otology. Journal of Laryngological Otolaryngology, 1961, 75, 614-620. ... Metz, O. The acoustic impedance measured on normal and pathological ears. Acta Otolaryngologica, Supplement, 1946, 63, 1-131. ...
Maximum acoustic power is transmitted when the acoustic impedance of the transducer material and the test fluid are identical; ... which separate the delicate electro-acoustic components from the test fluid with an acoustic waveguide, have been demonstrated ... Though direct contact between the ultrasound transducer and the test fluid yields strong signals, careful acoustic design might ... A wall between the transducer and test fluid might also be treated or conditioned to reduce the adverse effects of oxide in the ...
... because of its resonating transverse acoustic waves, has the potential to facilitate detections in an ... According to researchers, the acoustic impedances of water and ethanol obtained by their technique agree well with the reported ... Browse by Subject Lasers Optics Imaging Biophotonics Industrial Sensors & Detectors Test & Measurement Light Sources Fiber ... The teams experimental results show that the distributed acoustic impedance measurements of a material are possible using the ...
The impedance test battery was performed on seventy-six ears of pre-myringotomy children (Mean age: 4.6 years). The status of ... Acoustic reflex threshold and tympanometry were the most sensitive tests in predicting effusion. Multiple correlations between ... Impedance Audiometry in Serous Otitis Media Description: Effectiveness of impedance audiometry in diagnosing serous otitis ... A Test of the Degree of Association Among Selected Communication Characteristics and Innate Innovativeness Description: The ...
An ultrasound beam is reflected from any discontinuities in the acoustic impedance of the sample. The reflected ultrasound ... On-chip Self-test Circuitry: This circuitry, if present, increases the chip functionality by offering several design and test ... Scanning Acoustic Microscopy (SAM). FIG. 17 shows a schematic diagram of a scanning acoustic microscope (SAM). This shows an XY ... acoustic lens 406, transmitter 408,receiver 410, Z stage adjustment 412 (focusing), computer 414, and monitor 416. Acoustic ...
  • This work describes the assessment of the acoustic properties of sputtered tantalum oxide films intended for use as high-impedance films of acoustic reflectors for solidly mounted resonators operating in the gigahertz frequency range. (upm.es)
  • So, in a crazy way that I still don't understand yet, an output tranny works two ways -- (1) it steps-down the output tubes' plate voltage and high impedance to match the speakers, and at the same time (2) it steps up the impedance loading presented to the output tubes through the interaction of the tranny's primary and secondary windings (or, back impedance). (audiogon.com)
  • This Standard specifies maximum permissible ambient noise levels (MPANLs) allowed in an audiometric test room that produce negligible masking (less than or equal to 2 dB) of test signals presented at reference equivalent threshold levels specified in American National Standard S3.6-1996 American National Standard Specification of Audiometers. (nap.edu)
  • The MPANLs are specified from 125 to 8000 Hz in octave and one-third octave band intervals for two audiometric testing conditions (ears covered and ears not covered) and for three test frequency ranges (125 to 8000 Hz, 250 to 8000 Hz, and 500 to 8000 Hz). (nap.edu)
  • The Standard is intended for use by all persons testing hearing and for distributors, installers, designers, and manufacturers of audiometric testrooms. (nap.edu)
  • Conclusion The most evident alterations in the audiological evaluation were the prevalence of the descending audiometric con﫿guration between the frequencies of 2 and 4 kHz and the absence of the acoustic re﫿ex between the frequencies of 3 and 4 kHz bilaterally. (bvsalud.org)
  • The area under the receiver operating characteristic curve (AUC) was measured at audiometric frequencies between 1 and 8 kHz to determine TEOAE test performance in distinguishing SNHL from normal hearing. (elsevier.com)
  • Researchers at Ecole Polytechnique Fédérale de Lausanne (EPFL) observed that the hyper-frequency wave that regularly bounces off the fiber's walls creates an echo that varies, depending on the material the acoustic wave comes into contact with. (photonics.com)
  • Statistical Energy Analysis (SEA) has been used widely by industry and academia for more than 20 years to predict the mid-to-high frequency range behavior of complex acoustic systems. (sae.org)
  • All driver are in perfect working condition and have been thoroughly tested though the frequency range in our lab. (audiogon.com)
  • In addition to incorporating the 305mm (12in) bass driver with which AR introduced its acoustic suspension systems to home listeners, the AR-3a was the first speaker system to use two miniature hemispherical speakers developed by AR to give better midrange and high-frequency response. (audiogon.com)
  • 305 mm (12 in) acoustic suspension woofer, 38 mm (1 1/2 in) midrange hemispherical dome, 199 mm (3/4 in) high-frequency hemispherical dome. (audiogon.com)
  • In the rst case, piezoelectric transducers were utilized in order to excite low frequency Lamb waves while the panel was tested under static tensile loading. (spie.org)
  • Firstly, the FPGA generated waveform amplitude binary data based on direct digital frequency synthesis (DDS) technology, and then the data was converted into burst signal through an external daughter card, which included D/A conversion circuit, active low-pass filter, power amplifier circuit and impedance matching circuit. (bvsalud.org)
  • In music, acoustic waveguide methods, such as a large pipe organ or, for reproduction, exotic loudspeaker designs such as transmission line, rotary woofer, or traditional subwoofer designs can produce low-frequency sounds, including near-infrasound. (wikipedia.org)
  • With digital recording and a transmitting voltage of about 800 V a measuring uncertainty of the ultrasonic transfer time of 0,42 µs was obtainable for a green state SSiC-specimen with a minimal thickness of 40 mm and a test frequency of 600 kHz. (ndt.net)
  • The aimed measuring uncertainty for a cylindrical green ceramic body with a length of 372 mm amounted to 0,27% for a test frequency of 50 kHz. (ndt.net)
  • In order to develop these methods the linear scattering of low frequency waves by an orifice plate have been studied, using an acoustic two-port model. (diva-portal.org)
  • 7 In spite of patients' perception that the sounds were loud, hearing tests showed that the sounds occurred at intensities that were just barely greater than the softest sound audible at that frequency. (medical-journals.com)
  • I think many tech oriented members, such as Ralph (Atmasphere), Duke (Audiokinesis) and Al (Almarg) to name a few, have written extensively about Voltage and Power Paradigm amps, and how these amps produce current and power when presented with varying speaker impedances that change as a function of frequency. (audiogon.com)
  • That is, this class of tube amps is able to produce output voltages that don't vary very much as speaker impedance changes as a function of frequency. (audiogon.com)
  • And I think our tech members mentioned that if the output tubes are presented with a stepped up impedance that is outside the optimal design range of the output tubes, the result could be higher distortion and/or loss of power delivery capability at a given frequency as a function of the speaker's impedance characteristics at that frequency. (audiogon.com)
  • Double-evoked TEOAEs were measured using a chirp stimulus, in which the stimuli had an extended frequency range compared to clinical tests. (elsevier.com)
  • Conclusions: TEOAEs evaluated in an ambient condition, at TPP and in a power-weighted stimulus condition, had good test performance in identifying ears with SNHL based on SNR and CSM in the frequency range from 1 to 8 kHz and showed good test-retest reliability. (elsevier.com)
  • and identifying the acoustic speckle signal from the output signal transformed to the frequency domain. (google.com)
  • Once the nerve impulse is generated in the cochlea, the signal travels along the acoustic nerve to the cochlear nuclei. (vin.com)
  • Your child's audiologist will take a complete hearing history to help evaluate your child's hearing, There are many different types of hearing tests that can be used to check your child's hearing. (bcchildrens.ca)
  • For acoustic applications such as theaters, cinema halls, auditoriums the data on acoustic properties i.e. sound absorption coefficient and sound transmission loss are required to evaluate the acoustic behavior of panel products and to facilitate the necessary design computations. (scirp.org)
  • ABR testing may be used to evaluate central nervous system pathology such as eighth cranial nerve dysfunction from vascular compression or tumors and brainstem dysfunction. (unicare.com)
  • To evaluate in the diagnosis and monitoring of acoustic neuroma. (unicare.com)
  • Acoustic impedance of the new material is very nearly the same as water and its attenuation coefficient is lower than all other documented elastomers and many plastics. (olympus-ims.com)
  • Finally, the tool includes an acoustic attenuation section positioned on the body between the transmitter and the receiver. (google.ca)
  • The method for attenuating sonic waves generally includes transmitting a sonic wave from the transmitter to the tool, passing the sonic wave through the acoustic attenuation section, and receiving attenuated wave at the receivers. (google.ca)
  • 8. The apparatus of claim 1 wherein the acoustic attenuation section further comprises an o-ring on the inertial mass member for sealing the fluid within the gap, and a locking cap assembly for securing inertial mass member within the cavity. (google.ca)
  • 10. The apparatus of claim 1 wherein the acoustic attenuation section comprises three cavities, each oriented about 120 from the other two cavities. (google.ca)
  • Application of this computational procedure to the measured tracheal acoustic impedances of 15 human subjects will illustrate the program's capability toward early detection of lung dysfunction using a prototype clinical facility. (cdc.gov)
  • A huge variety of characterization and analyses tools are available such as for measurement of the thermal impedance of power devices, lock-in thermography, scanning acoustic microscopy, static and lock-in thermography, scanning electron microscopy, focused ion beam sectioning and others. (fraunhofer.de)
  • In this work, different kinds of ultrasonic dry coupling will be tested for their sensitivity and lateral resolution to detect material mismatches. (ndt.net)
  • Alterations in vestibular examinations occurred in 90% of patients, mostly in the caloric test, with a predominance of deficient central vestibular system dysfunction. (bvsalud.org)
  • A test used to observe hearing behaviour to sound when the head turn test (VRA above) is not possible. (bcchildrens.ca)
  • A test that uses playing games in response to sound. (bcchildrens.ca)
  • Loudness as herein computed, depends upon the acoustic properties of a sound that impinges upon a normal-hearing listener. (nap.edu)
  • Types of testing conducted in the ATF include Transmission Loss, Sound Power, and Vibration testing. (sae.org)
  • The study was carried using acoustic pulse tester based on standing wave method for evaluating sound absorption coefficient. (scirp.org)
  • Rather than using light directly, Antman came up with the idea to use light transmitted through optical fibers to create sound waves , or acoustic vibrations, taking advantage of a phenomenon known as stimulated Brillouin scattering. (phys.org)
  • With these methods it is possible to capture both the complex flow, with sound generating mechanisms, and acoustic - flow interactions. (diva-portal.org)
  • Subjective tinnitus, which we refer to as tinnitus, is the false perception of sound in the absence of an acoustic stimulus. (medical-journals.com)
  • At the time I bought these speakers, I owned a pair of Spica Angelus speakers (Stereophile Class B). I found through A/B testing that the quality and character of sound produced by the AE109s was better than the Spicas with excellent imaging characteristics. (audiogon.com)
  • The ANSI/ASA S12.42-2010 requires that impulse tests be performed at three ranges of impulse peak sound pressure levels. (cdc.gov)
  • The standard recommends generating the required impulse sound events using explosive charges or an acoustic shock tube. (cdc.gov)
  • Purolator acoustic Poromesh® and Poroplate® diffusion bonded porous metals are used to provide acoustic flow resistance for Helmholtz resonator sound absorption applications and other noise abatement applications. (purolator-facet.com)
  • The flow resistance required for optimum operation is determined by analysis of sound energy levels, complex acoustic impedance requirements for a sound absorbing structure and correlation of these with steady state fluid flow resistance of permeability values. (purolator-facet.com)
  • Impedence testing showed a large shift in tympanogram configuration from B to C, indicating that cartilage grafts heal with integrity and measurable mobility although stiffened compared with normal. (elsevier.com)
  • Pulse-echo, phase-amplitude and amplitude-mapping approaches constitute the conceptual bases for three fundamentally different types of acoustic imaging systems and can be used for categorizing the systems. (ebooks.com)
  • In addition to accommodating typical types of acoustic testing, the ATF has some unique capabilities. (sae.org)
  • It has to be kept in mind that hearing itself is a much more complex phenomenon then can be appreciated from hearing assessment tests used in animals. (vin.com)
  • For pre- and post-treatment assessment, the Sensory Organization Test (SOT) protocol of the Computerized Dynamic Posturography (CDP) and two scales of balance self-perception, Activities-specific Balance Confidence (ABC) and Dizziness Handicap Inventory (DHI), were used. (bvsalud.org)
  • The Abdomen, Adult Echocardiography, Obstetrics and Gynecology, Sonography Principles & Instrumentation, and Vascular Technology Examinations are quite simply an objective assessment of a test taker's requisite foundation of knowledge and skills. (mometrix.com)
  • The main difference between ASSR and ABR is that ASSR is usually faster to show that hearing is normal because both ears can be tested at the same time, whereas with ABR, each ear must be tested one at a time. (bcchildrens.ca)
  • A test that uses sounds at different volumes and pitches with headphones over your child's ears. (bcchildrens.ca)
  • The objective of this study was to compare TEOAEs from 0.79 to 8 kHz using these three stimulus conditions in adults to assess test performance in classifying ears as having either normal hearing or SNHL. (elsevier.com)
  • 6. Apparatus for serially monitoring intracranial pressure comprising means for the acoustic stimulation of a stapedial muscle, means for obtaining a measurement related to the magnitude and direction of the responsive volume displacement of the associated ear drum, means for comparing said measurement with pre-established reference data derived from the measurement of intracranial fluid pressure by other means and read-out means to display the results of said comparison. (google.com)
  • The major function of the middle ear is to match relatively low impedance airborne sounds to the higher impedance fluid of the inner ear. (vin.com)
  • The invention provides a method and an apparatus for measuring the size, concentration and size distribution of particles in a fluid by determining the characteristics of an acoustic speckle signal of the particles and relating these characteristics to the size and concentration characteristics of the. (google.com)
  • 1. A method for determining the size of particles in a fluid comprising the steps of obtaining an acoustic speckle signal of the particles in the fluid and deriving the size of the particles in the fluid from the acoustic speckle signal. (google.com)
  • 3. The method as set forth in claim 2 , wherein the input signal is focused on a focal region in the fluid and some of the input signal is scattered by particles in the focal region, and wherein the output signal is limited to the portion of acoustic energy scattered by particles in the focal region. (google.com)
  • Most audiologists will use several different tests to get a complete picture of your child's hearing. (bcchildrens.ca)
  • A hearing test that uses small disk-like sensors attached with adhesive to the baby's scalp. (bcchildrens.ca)
  • This test measures the hearing nerve activity in response to the sounds. (bcchildrens.ca)
  • This hearing test is typically done for infants over six months of age. (bcchildrens.ca)
  • This test does not show whether the hearing is normal. (bcchildrens.ca)
  • This is a sleeping hearing test. (bcchildrens.ca)
  • This is the basic level where incumbents perform responsible professional work in administering standard diagnostic tests, evaluating the extent of any hearing impairment and conducting aural rehabilitation sessions. (ok.gov)
  • The audiologist's hearing test battery contains new diagnostic tests, many based on modern technological advances. (springer.com)
  • Judging hearing in humans can be relatively straightforward with behavioral tests or more objectively with electrophysiological tests. (vin.com)
  • In-depth survey report: design and construction of an acoustic shock tube for generating high-level impulses to test hearing protection devices. (cdc.gov)
  • In order to accurately assess the performance of these types of protectors, the American National Standards Institute revised the ANSI/ASA S12.42 (ANSI, 2010) standard to include a method to measure the impulse peak insertion loss of all hearing protectors over a wide range of impulse levels using a dual-ear acoustic test fixture and a field microphone. (cdc.gov)
  • Preferably eardrum displacement is used as a baseline measure and acoustic compliance measurement records short-term variation, the two records being combined by computer. (google.com)
  • While there is a plenty of information on foam based absorption, there is a lack of data related to acoustic properties of wood and wood based panel products. (scirp.org)
  • Affixed directly to the surface of an ISO 10844 regulated test track, Type 9740 is used to measure the absorption coefficient of the asphalt without drilling a core sample according to ISO 13472-2. (bksv.com)
  • Acoustic stimulation methods applied during sleep in young adults can increase slow wave activity (SWA) and improve sleep-dependent memory retention. (frontiersin.org)
  • The aim of this study was to determine if acoustic stimulation can increase SWA and improve declarative memory in healthy older adults. (frontiersin.org)
  • Thirteen participants 60-84 years old completed one night of acoustic stimulation and one night of sham stimulation in random order. (frontiersin.org)
  • Overnight improvement in word recall was significantly greater with acoustic stimulation compared to sham and was correlated with changes in SWA between ON and OFF intervals. (frontiersin.org)
  • Using the phase-locked-loop method to precisely target acoustic stimulation to the upstate of sleep slow oscillations, we were able to enhance SWA and improve sleep-dependent memory storage in older adults, which strengthens the theoretical link between sleep and age-related memory integrity. (frontiersin.org)
  • This analytical procedure computes a person's partial lung volume from an experimental two-microphone acoustic measurement of the upper airway passages obtained through a molded tubular mouthpiece. (cdc.gov)
  • LAUSANNE, Switzerland, July 31, 2018 - Forward stimulated Brillouin scattering (FSBS), because of its resonating transverse acoustic waves, has the potential to facilitate detections in an optical fiber's surroundings. (photonics.com)
  • Some tools dedicated to input impedance calculation or measure-ment exist, but they either allow only for brass wind instruments anal-ysis (such as the BIAS/VIAS software suite provided by ARTIM: http://artim.at/?page_id=2&sprache=2) or are not eas-ily usable for instrument makers (ARTOOL, available as a C++ library and API for simulating instruments: http://artool. (slideshare.net)
  • Researchers have now demonstrated a technique to measure the distributed FSBS spectrum of an optical fiber and retrieve the local acoustic impedance of the surrounding materials. (photonics.com)
  • To test the technique, researchers immersed optical fibers first in water and then in alcohol, before leaving them out in the open air. (photonics.com)
  • By treating the outer surface in a way that would attract the chemical of interest, the researchers theorize that the acoustic waves would be modified in a detectable way when the target chemical attaches to the fiber. (phys.org)
  • Our company's name is Mometrix Test Preparation, and we have a team of standardized test researchers who have worked on developing our study guide for the ARDMS test. (mometrix.com)
  • The ultrasonic diagnostic apparatus radiates an ultrasonic wave generated from an ultrasonic transducer built in an ultrasonic probe into a subject, and receives a reflected wave caused by a difference in acoustic impedance of the subject tissue by the ultrasonic probe. (google.com)
  • The new approach works by using optical waves that are intense enough to create an acoustic vibration that reaches outside of the fiber. (phys.org)
  • This document does not address ABR or OAE for neurologic conditions, such as multiple sclerosis (MS), or when used as part of intra-operative monitoring (for example, during surgery for acoustic neuroma). (unicare.com)